Limit-switch mechanism.



W. N. DICKINSON. y LIMIT SWITCH MECHANISANI. APPLICATION man JUNE 11, 19:6.

15,249,943 Patented Deo. 4, 1917 2sHEETs-SHEET if IUI I l IIIIIIIIII M W. N. DICKINSON.

LIMIT SWITCH MECHANISM.

APPLICATloN men JUNE 17. 1915,

I. ,Q43 Patented Dec. 4, 19V?.

2 SHEETSSHEET 2.

A TE@ STATE@ Barnim ernten.

WILLIAM NOBLE drircknvsoiv,A OEBROOKIYNQNEW YORK, nssrelvon, BY Masiva Assiem- UME-Nrs, To STANDARD PLUNGERELEVATOR Ger/Iran?, .e eoaroanrroiv or MASSA- cHUsET'rs. d

Y tomatically shut-rolf, the power at apredec has other applications.

termined point irrespectivedof the eperator, andhas for its objectthe production of a stop motion switchwhich will operatevunder the requirements j of certain conditions, which apparatusfnow available will, not

meet, Y l I shall describe my device as applied to a drum type ofelectric elevator, but wish it distinctly understood thatI do not, mean to limit myself thereby, as it will be evident 'to those skilled in theart thatmy invention In such electric elevators, ther'hoisting cables are attached at one end tothe car and at the other lend to the `hoisting drum. I The automatic stop motion device is appliedto `the machine, direct or through gearing or 4'other means and is designed to automatically bring the drum tof rest, and hence thecar, at

predetermined limitsof travel `in the event thatthe operator neglectsto bring the machine to rest bymeans of the'control in the car. This is accomplishedA by. opening the main circuit-leading to -amechzanically cony, trolled switch or switches. `'lheseare `someltimes so arranged that when the machine is automatically broughtto rest, yin either direction by means' of such device, it cannot again be started in eitherfdirection by means of the` ordinary control device, placed at the at other times,fthe device is disposal of the operator,on the car, while so arranged,

r that should it automaticallybring thema- Y up, direction, the' operator` Hdown direction by means l.form y of control 1 placed whether an `the car or` ata chine Vto restgwith the car going, say in the could` start itin of the` ordinary at his disposal, landing, and vice versa.- In practically all of these arrangements, however, arranged, althreaded shaft 0r sleeve-1S Prevlded 4vhf-h maybe an @X- l Specification of Letters Patent. Y Applicatiomled June 17, `191,6. Serial'No. 104,344.

LIMlT-swrrcn MEGHANISM.

PatentedDec. d, 1917.

tension of `the drum shaft, or spur geared or miter geared or chain geared, or otherwise depending for its motion upon the turning of Vthe drum `carrying lthe lifting cable or some part of the elevator systemV to which the-machine or `cable transmit motion.` On 'this threaded shaft or sleeve ajnut is `threaded ywhich normally prevented from revolvingwith the thread when the drum isin c motion, by means of aweight, spring or other device, but whichtravels laterally along the shaft or sleeve in one direction or the other asthe shaft is revolved, until it comes into contact with a locking device, either adment of the desired result of speed changing orstopping or regulation required.` In

electric elevators, the customary d form` of Vthis accomplishment .end of the device includes a cam and a switch or several cams and switches or,` other vdirect or intermediately operatingV devices for'the up motion and a similar set for the down` motion or lmotion in the opposite direction. In some of these the circumferential motion of the part actuated by the traveling nut, whenfit `is acis limited to less than 180 degrees, while in tuated to revolve with the threaded shaft,

Y others, a geared or an intermittent motion is `introduced between the part` actuated by the threaded shaft and tie switch or mechanical` stopping device, to permit of a greater movement than 180 degrees of the part actuated by the threaded shaft.

In my device a similar traveling nut and locking devices are used but `I provide a means for opening the switch which is not limited to any degree of travel of the drum. `I-Iaving set forth my invention I will now specifically set forth an embodiment thereof.

In the drawings: i Figure Iis a topview of my limit switch mechanism.

Fig. II is a side view thereof. Fig. `III is a similar side view showing a modification of some of fthedetails thereof.

Fig.` IV is a front view of my switch.

Fig. V is a top view thereof.

Figs. VI and VII show the switchopen and shut.

Figs. VIII and IX show a modication of the switch in open and closed positions.

17 in the cam. reach or pass the contact end the switch lever, bythe centering device employed or by other means, and if motion were continued the switch lever would be thrown in the opposite direction by the continued movement of the cam toward its original position. I call attention to this point as under certain conditions it might prove desirable to take advantage of this feature. It will further be clear that while the drawings of my invention indicate a switch arm leading from one side of an electric circuit to the two contacts which control the up movement and the down movement of the elevator, the breaking of th-e circuit to either of which stationary contacts will stop the mov-ement ofthe elevator in its respective operation while still maintaining the contact intact to permit of the movement of the elevator in the opposite direction, these circuits are permissible of changes which will occur to those skilled in the art and further it will be clear that by lengthening` the arm or broadening the arm, a multiplicity of contacts may be arranged on eitheror both sides of the switch lever, in such manner that circuits will be opened and closed either simultaneously or in different time relation, due to either angular displacement of the switch arm by a single dwell in" the cani or by different dwells or `different formation of the cam surface for the purpose of the electrical connections or the mechanical movements by means of the switch arm or its counterpart, in a mechani-` cal device to meet the requirements of the individual case. It will be clear that the contacts or mechanical movements affected by angular displacement or the switch arm or its counterpart may be either fixed or adjustable as requirements may demand.l

The stop motion switch illustrated and described is in the form which I desire to Copies of this patent may be obtained for five cents each, by addressing the `construct it, but any changes or modifications may be made without departing from the salient features of my invention; and I, therefore, intend the following claims to cover such modifications as naturally fall within the lines of invention.

I claim:

l. Ina limit switch, of the class described, in combination, a j ournaled screw, a nut on the scr-ew suitably held from revolving during a portion of its travel without interfering with its longitudinal movement on the screw, adjustable striking nuts mounted on the screw to limit the movement of the traveling nut without revolving, ai pivotedly mounted lever arm, two spring contacts, both contacting with the before-mentioned arm in its central position, a cam adapted to move the lever arm in either direction and normally hold it in its central position, means operated by the traveling nut when it revolves for moving the cam, whereby contact between the lever and one of the beforementione'd spring contacts is continuous while the contact between the lever and the opposite spring contact is broken.

2. In a limit switch, of the class described, in combination, a screw mounted so as to revolve in either direction, a nut on the screw with means to normally prevent its revolving without interfering with its longitudinal travel, adjustable stops to limit the travel of the nut without revolving the nut, a pivotedly mounted lever, a plurality of contacts oppositely opposed contacting with the before-mentioned lever in its central position, means to normally hold the lever in its central position, means to move the lever out of its central position when the traveling nut contacts with its stop and revolves with the screw.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM NOBLE DICKINSON.

Witnesses:

F. MCALEER, P. D. CASE.

Commissioner of Patents,

Washington, D. C. 

